Design of IPMSM Rotor Shape for Magnet Eddy-Current Loss Reduction

In this paper, an interior permanent magnet (PM) synchronous motor (IPMSM) with concentrated windings was designed for railway traction applications. This IPMSM was analyzed using a 2-D FEM. The results showed that the designed IPMSM has a significant PM eddy-current loss. For more accurate calculation, a 3-D FEM analysis was carried out. Further, the PM eddy-current loss was reduced without critical torque reduction by changing the position of the magnets at the rotor. Finally, frequency analysis of air-gap magnetic flux density waveforms was carried out to investigate the effect of magnet placement on the eddy-current loss.